Traditional inlet valve, as figured in FIG. 1, is applied with Pascal's Principle (backpressure type), the water stop padding is disposed with a through hole 200, the through hole 200 is coupled to the valve spool 201 of the valve cover (the valve spool 210 can be independent), the valve spool 201 is disposed with a thin groove 202. The disadvantages are that: if the water quality is bad, the groove 202 is easily blocked by the dirt in the water, it makes it unable to form backpressure to the water stop padding, thus making the inlet valve unable to stop water. Besides, when to wash the valve spool 201, it needs professional person to disassemble, it is difficult for ordinary to operate.